Multi-data-rate optical transceiver

ABSTRACT

An optical transceiver module includes an optical-to-electrical converter configured to convert a first optical signal to a first electric signal, a first amplifier configured to amplify the first electric signal, a bandwidth controller coupled to the first amplifier, configured to control the frequency response characteristics of the amplification of the first amplifier to produce a first amplified electric signal, a driver circuit configured to receive a second electric signal and to produce a second amplified electric signal in response to the second electric signal and an optical feedback signal, an electrical-to-optical converter coupled to the micro-controller and configured to convert the second amplified electrical signal to a second optical signal, and a photo diode configured to detect the second optical signal and to produce the optical feedback signal to be received by the driver circuit.

CROSS-REFERENCES TO RELATED INVENTIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/257,627, filed on Oct. 25, 2005, now U.S. Pat. No.7,200,336. The present invention is related to commonly assigned U.S.patent application Ser. No. 10/741,805, filed on Dec. 19, 2003, titled“Bi-directional optical transceiver module having automatic-restoringunlocking mechanism”, commonly assigned U.S. patent application Ser. No.10/815,326, filed on Apr. 01, 2004, titled “Small form factor pluggableoptical transceiver module having automatic-restoring unlockingmechanism and mechanism for locating optical transceiver components”,commonly assigned U.S. patent application Ser. No. 10/850,216, filed onMay 20, 2004, titled “Optical Transceiver module having improved printedcircuit board”, commonly assigned U.S. patent application Ser. No.10/893,803, filed on Jul. 19, 2004, titled “Single fiber opticaltransceiver module”, and commonly assigned Chinese Patent ApplicationNo. 200420034040.X filed on Jun. 15, 2004, titled “An APD Bias VoltageTest Equipment”. The disclosures of these related applications areincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to electro-optical devices, specifically, anoptical transceiver.

BACKGROUND

An optical transceiver is a device that can covert convert opticalsignals into electrical signals and convert electrical signals intooptical signals. Various standards in the telecommunication and datacommunication industries specify the rates of data transmissions. Forexample, the original Ethernet standard has a data rate of 10 Mega bitper second (Mbps). Fast Ethernet's data rate is 100 Mbps, and GigabitEthernet transmits and receives data at a rate of 1000 Mbps. Compliancewith the standards is important for inter-operatability interoperabilitybetween different vendors for a wide range of commercial applications.Different industry standards such as the IEEE standard includerequirements on the optical interface of an optical transceiver.Particularly, the average output power of an optical transceiver for the100 Mbps Ethernet is between −20 and −15 dBm, while that for the 1000Mbps Ethernet is between −10 and 4 dBm. Similarly, the required averageinput power for 100 Mbps Ethernet is from −30 dBm to −15 dBm while thatfor 1000 Mbps Ethernet is from −17 dBm to −3 dBm. The currentlycommercially available optical transceivers interface include only fixeddata rate under a fixed optical specification. There is therefore a needfor networks operating at different data rates to properly communicatewith each other. There is also a need for networks to upgrade to higherdata rates without excessive costs and time.

SUMMARY

In one aspect, the present invention relates to an optical transceivermodule, comprising an optical-to-electrical converter configured toconvert a first optical signal to a first electric signal; a firstamplifier configured to amplify the first electric signal; a bandwidthcontroller coupled to the first amplifier, configured to control thefrequency response characteristics of the amplification of the firstamplifier to produce a first amplified electric signal; a driver circuitconfigured to receive a second electric signal and to produce a secondamplified electric signal in response to the second electric signal andan optical feedback signal; an electrical-to-optical converter coupledto the micro-controller and configured to convert the second amplifiedelectrical signal to a second optical signal; and a photo diodeconfigured to detect the second optical signal and to produce theoptical feedback signal to be received by the driver circuit.

In another aspect, the present invention relates to an opticaltransceiver module, comprising an optical-to-electrical converterconfigured to convert a first optical signal to a first electric signal;a first amplifier configured to amplify the first electric signal; abandwidth controller coupled to the first amplifier, configured tocontrol the frequency response characteristics of the amplification ofthe first amplifier to produce an first amplified electric signal; adriver circuit configured to receive a second electric signal and toproduce an amplified electric signal in response to the second electricsignal and a optical feedback signal; an electrical-to-optical convertercoupled to the micro-controller and configured to convert the amplifiedelectrical signal to a second optical signal; an optical data-ratedetector configured to detect the second optical signal and to producethe optical feedback signal to be received by the driver circuit; anoptical interface configured to receive the first optical signal andoutput the second optical signal; and an electrical interface configuredto receive the second electrical signal and output the first amplifiedelectrical signal.

In yet another aspect, the present invention relates to an opticaltransceiver module, comprising an optical-to-electrical converterconfigured to convert a first optical signal to a first electric signal;a first amplifier configured to amplify the first electric signal; abandwidth controller coupled to the first amplifier, configured tocontrol the frequency response characteristics of the amplification ofthe first amplifier to produce an a first amplified electric signal; adriver circuit configured to receive a second electric signal and toproduce an amplified electric signal in response to the second electricsignal and a an optical feedback signal; an electrical-to-opticalconverter coupled to the micro-controller and configured to convert theamplified electrical signal to a second optical signal; an opticaldata-rate detector configured to detect the second optical signal and toproduce the optical feedback signal to be received by the drivercircuit; an optical interface configured to receive the first opticalsignal and output the second optical signal; and an electrical interfaceconfigured to receive the second electrical signal and output the firstamplified electrical signal.

Embodiments may include one or more of the following advantages. Thedisclosed system provides a flexible multi-rate optical transceiver thatenables a computer network to operate at different data rates.

Another advantage of the disclosed system that it allows networks orcomputer devices operating at different data rates to communicate witheach other.

Yet another advantage of the disclosed system that it providesconvenient means for upgrading a network or computer system from onedata rate to a different data rate. The manual unplugging and pluggingof optical transceivers on a network are eliminated during a data rateupgrade.

Still another advantage of the disclosed system that the multi-rateoptical transceiver is more cost efficient by providing the capabilityof communicating at multiple data rates in one optical transceiver.

Another advantage of the disclosed system that it provides softwarecontrol of an optical interface to allow data transmission at differentdata rates and, compatible with communication standards at the differentdata rates.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an exemplified optical transceivermodule in compatible with the present invention.

FIG. 2 is a chart for average power input and output for 100 Mbps and1000 Mbps Ethernet in accordance with the present invention.

FIG. 3 is a block diagram for a multi-rate optical transceiver inaccordance with an embodiment of the present invention.

FIG. 4 is a block diagram for a multi-rate optical transceiver with anelectrical Media Independent Interface in accordance with anotherembodiment of the present invention.

FIG. 5 is a block diagram for a multi-rate optical transceiver withautomatic data rate detection in accordance with another embodiment ofthe present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with thepreferred embodiments, it will be understood that they are not intendedto limit the invention to these embodiments. On the contrary, theinvention is intended to cover alternatives, modifications andequivalents, which may be included within the spirit and scope of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it will be obvious toone of conventional skill in the art that the present invention may bepracticed without these specific details. In other instances, well knownmethods, procedures, components, and circuits have not been described indetail as not to unnecessarily obscure aspects of the present invention.

FIG. 1 shows an optical transceiver 100 that can receive optical signalsfrom an optical fiber and coverts convert the received optical signalsinto electrical signals. The optical transceiver 100 can also convertelectrical signals into optical signals and transmits transmit theconverted optical signals to an optical fiber. The optical transceiver100 include includes an electrical to optical converter (for transmitpurposes), and an optical-to-electrical converter (for receivepurposes), a driver providing proper bias voltage and modulation fortransmission of the output optical signals, and a limiting amplifierproviding proper signal amplification for the optical-to-electricalconverter.

It is desirable for an optical transceiver to be in compliance withindustry standards. The different industry standards have define definedrequirements on the optical interface and the electric interface of anoptical transceiver. In particular, different industry standards requiredifferent input and output powers to and from an optical transceiver.FIG. 2 shows an example of the average input and output powerrequirements for 100 Mbps and 1000 Mbps Ethernets.

A conventional optical transceiver is built to transmit and receive dataat a fixed data rate. An optical transceiver for 100 Mbps Ethernetcannot be used on a 1000 Mbps Ethernet network. However, it is verycommon that a server and its clients work at different data rates (aserver working at 1000 Mbps and some of its clients working at 100 Mbpswhile its other clients working at 1000 Mbps for example). In thissituation, the server needs to be connected with a plurality of opticaltransceivers that each operates at a different data rate. Furthermore,when a communication device needs to be upgraded from one data rate(e.g. 100 Mbps) to another data rate (e.g. 1000 Mbps), all the oldoptical transceivers have to be replaced by new optical transceiverscapable of transmitting data at the new data rate. The upgrade can thusbe costly and time consuming.

For an optical transceiver to operate on multiple data rates, it isdesirable to be able to transmit and receive data at multiple data ratesat both its electrical interface and its optical interface. The industrystandard interfaces for the electrical interface side include forexample the Media Independent Interface (MII) and the Gigabit MediaIndependent Interface (GMII).

On the optical interface side, there has not been a standard solution.The fundamental requirement for a multi-rate optical transceiver is toenable the transceiver to transmit and receive optical signals using avariable input power and a variable output power that satisfy therequirements from various industry standards. In particular, theelectrical-to-optical converter needs to output optical signals at avariable output power. The optical-to-electrical converter needs tooperate at different sensitivities, in reflect respect of differentinput powers for different data rates.

ReferReferring to FIG. 3, a block diagram illustrating the transmissionand reception paths of an optical transceiver 300 is shown. In thetransmission path, the optical transceiver 300 receives a secondelectrical signal 330 (also referred to as an electrical transmissionsignal). The electrical transmission signal 330 goes through block 312,which generates a driver current for electrical to optical converter311. Block 312 also generates a bias voltage for the electrical tooptical converter 311. The driver current and the bias voltage arecontrolled by a micro-controller 313. The electrical to opticalconverter 311 generates a second optical signal 360 (also referred to asan optical transmission signal). The optical transmission signal 360 ismonitored by monitoring photo-diode 317, which sends a feedback signalthrough feedback control line 319 to driver 312, so that the biasvoltage and driving current can be modified. When there is a change indata rate at the electrical transmission signal 330, the data rate ofthe optical transmission output signal 360 can be changed by a usercommand line 340. Through the user command line 340, a control signal issent to micro-controller 313. The micro-controller 313 controls thedriver 312 that produces the bias voltage and driving current forelectrical to optical converter 311. Different bias voltages and drivingcurrents can cause the electrical to optical converter 311 to producedifferent output power powers for the optical transmission signal 360.

The output power of the optical output signal 360 can be furthercontrolled by a an optical feedback signal through the feedback controlline 319. A monitoring photo diode 317 receives and monitors theintensity of the monitoring optical signal 321 from the electrical tooptical converter 311 and produces the feedback control signal inaccordance with the intensity of the monitoring optical signal 321. Thefeedback signal can adjust the bias voltage or driving current of block312 to control the output power of the optical transmission signal 360.

In the reception path, the optical transceiver 300 takes a first opticalsignal (i.e. the optical reception signal) 350, and the opticalreception signal 350 is converted to a first electrical signal (i.e. thereception electrical signal) at optical-to-electrical converter 314. Theconverted electrical signal is amplified by Trans-Impedance Amplifier(TIA) 315, followed by a limiting amplifier 316. The amplification canbe modified by TIA bandwidth controller 318.

When there is a change in the data rate in the optical reception signal350, the sensitivity for the optical reception signal 350 needs to bemodified to fit the reception data rate. This is done by the bandwidthcontroller user command input 370. This control signal is received bybandwidth controller 318, which controls the bandwidth of theTrans-Impedance Amplifier 315. Different bandwidth at the TIA 315 makesthe sensitivity of the electrical signal from the optical-to-electricalconverter 314 different. Thus the optical transceiver 300 can beadjusted to receive data at different data rates.

A variety of implementations exist for the control lines 340 and 370.Control lines 340 and 370 can be a single control that can set datatransmission and reception at the same data rate. Alternatively, thecontrol lines 340 and 370 can be implemented by two separate controllines, allowing different data rates for data transmission andreception. In one implementation of the control lines 340 and 370, thecontrol lines simply send a “mode” signal, informing the opticaltransceiver the desired data rate to be set. Once the mode signal isreceived, the optical transceiver is programmed to automatically set theoperation parameters to a set of pre-determined values such that theproper data rate can be achieved. The “mode” signals can be prepared andstored in one of the following forms:

1. a programmable logic such as CPLD or FPGA

2. a memory device, such as EEPROM

3. a micro-controller (with build built in memory to store softwareinstruction)

In another implementation of the control lines 340 and 370, the controlsare achieved through an “in-band” hand-shaking from the opticalinterface. The operation mode of the optical transceiver is determinedthrough this hand shake optical interface, by an intelligent dataprocessing unit so that the optical transceiver can be set at the properdata rate through the “remote” provisioning by the link party at the farside.

FIG. 4 illustrates another optical transceiver 400. In the transmissionpath, the optical transceiver 400 receives an electrical transmissionsignal at a Physical Coding Sublayer (PCS) block 420 which in turntransmits the electrical transmission signal to a Physical MediaAttachment (PMA) block 419. The electrical transmission signal from thePMA block 419 goes through block 412, which generates a driver currentfor electrical to optical converter 411. Block 412 also generates a biasvoltage for the electrical to optical converter 411. The driver currentand the bias voltage are controlled by micro-controller 413. Theelectrical to optical converter 411 generates an optical transmissionsignal 470. The optical transmission signal 470 is monitored bymonitoring photo-diode 417, which sends a feedback signal throughfeedback control line 490 to driver 412, so that the bias voltage anddriving current can be modified.

When there is a change in data rate at the electrical transmissionsignal 430 440, the data rate of the optical transmission output signal470 can be changed by a user command line 450. Through the user commandline 450, a control signal is sent to micro-controller 413, whichcontrols the driver 412 which in turn produces the bias voltage anddriving current for electrical to optical converter 411. Different biasvoltages and driving currents cause the electrical to optical converter411 to produce different output power for the optical transmissionsignal 470.

The output power of the optical output signal 470 can be furtherregulated by setting different values to an EEPROM POT in the controlfeedback loop . . . by the optical feedback signal through the feedbackcontrol line 490, which is generated by monitoring photo diode 417. Themonitoring photo diode 417 receives and monitors the strength of amonitoring optical signal 421 from the electrical to optical converter411. Based on the strength of the monitoring optical signal 421, themonitoring photo-diode 417 produces the feedback control signal on thefeedback control line 490. The feedback signal reduces or increases thebias voltage or driving current of block 412, which results in areduction or increase in the output power of the optical transmissionsignal 470.

In the reception path, the optical transceiver 400 receives an opticalreception signal 460, and the optical reception signal 460 is convertedto a reception electrical signal at optical-to-electrical converter 414.The converted electrical reception signal is amplified byTrans-Impedance Amplifier (TIA) 415, followed by a limiting amplifier416. The amplification can be modified by TIA bandwidth controller 418.

When there is a change in the data rate in the optical reception signal460, the optical reception signal 460 is modified to fit the receptiondata rate by adjusting controller user command input 480 to thebandwidth controller. Based on the user command input 480, the bandwidthof Trans-Impedance amplifier 415 can be modified. Different bandwidthsat the TIA 415 can result in different sensitivities to the electricalsignal in the optical-to-electrical converter 414. Thus the opticaltransceiver 400 can be adjusted to receive data at different data rates.

The PMA 419 and PCS 420 are electric circuits that enable in thecompatibility with the Ethernet standards such as the Media IndependentInterface (MII) standard or the Gigabit Media Independent Interface(GMII). With the configuration in FIG. 4, the interface of signals 430and 440 become “universal” with any GMII (Gigabit Media IndependentInterface) type of interfaces. With a GMII interface, data can betransmitted at different data rate such as 100 Mbps or Gigabit Ethernetthrough the same interface without any need for changing the physicaloptical interface device. This is achieved by integrating theintelligence of switching the operation mode of PHY also inside thetransceiver. Data Encoding and Decoding can be conducted without anyphysical change. For example 100 M Ethernet requires 4B/5B CODEC whileGigabit Ethernet requires 8B/10B CODEC. With this “switchable” functionintegrated into the optical transceiver, it becomes a “universal device”for running both Fast Ethernet and Gigabit Ethernet. A user can attachthis device to their MII or GMII based MAC interface and set data rateby software commands without changing the physical configuration of thedevice.

In another embodiment, the optical transceiver's transmission andreception data rates can be detected and the optical transceiver'soperation mode can be set automatically based on the detected transmitand reception data rates. FIG. 5 shows the block diagram for an opticaltransceiver 500. As for optical transceiver 400, optical transceiver 500has a Physical Coding Sublayer (PCS) block 520 at its electricalinterface. At this interface, electrical transmission signal 540 entersthe PCS 520 and electrical reception signal 530 is sent out by the PCS520. The PCS 520 is coupled with a Physical Media Attachment (PMA) block519. The combination of the PCS 520 and the PMA 519 makes the electricalinterface a standard Ethernet interface making it possible for theoptical transceiver to be connected directly to an Ethernet Media AccessController (MAC) block.

On the optical interface, the optical transmission signal 570 is theoutput from the electrical-to-optical converter 511. The opticalreception signal 560 enters the optical-to-electrical converter 514. Themajor control of the output power of optical transmission signal 570 isfrom control input 550, and a fine tune control signal 590 comes frommonitoring photo-diode 517. The control of the input sensitivity ofoptical reception signal 560 is through bandwidth controller 518, whichis controlled by control signal 581. Unlike ptical optical transceiver400, whose data rate is entirely controlled by user command lines,optical transceiver 500 can detect the data rates at the electricaltransmission signal 540 and the reception optical signal 560.

In the transmission direction, the transmission data rate detector 521detects the electrical transmission signal 540 and measures thetransmission signal data rate. One possible implementation of the datarate detector 521 can comprise a clock recovery circuit and a counter.The counter of clock cycles is an indication of the data rate. Based onthe measured transmission signal data rate, the transmission data ratedetector 521 generates a Micro-controller data rate set up input signal550 and sends this control signal to micro-controller 513.

In the data-reception path, the reception data rate detector 580receives the electrical reception signal from output of theoptical-to-electrical converter 514 and measures the data rate of thissignal. Based on the measured data rate of the input optical data, thereception data rate detector 580 generates a bandwidth controller set upinput 581, and sends this control signal to bandwidth controller 518.With the detection of the transmission and reception data rates, thedata rates of the optical transceiver 500 can be automatically set bythe data rate detectors 521 and 580, thus the user command lines can beeliminated.

The disclosed system includes the following advantages over theconventional single-data-rate optical transceiver: (1) A multi-rateoptical transceiver makes it possible to a network to operate atdifferent data rates or for networks or computer devices operating atdifferent data rates to communicate with each other. (2) A multi-rateoptical transceiver makes it more convenient to upgrade a network fromone data rate to a higher data rate. No unplugging and plugging ofoptical transceivers on a network is needed during a data rate upgrade.(3) A multi-rate optical transceiver is more cost efficient. Themulti-rate optical transceiver can operate on multiple data rates, whileseveral conventional single-data-rate optical transceivers are requiredto operate at different data rates.

PART NUMBERS

-   100 optical transceiver module-   110 module housing-   120 shielding metal cover-   130 electrical interface-   140 optical interface-   200 a chart for average input and output powers of 100 Mbps and 1000    Mbps Ethernet-   311 Electrical to optical converter device-   312 driver circuits-   313 micro-controller/EEPOT-   314 optical-to-electrical converter-   315 trans-impedance amplifier-   316 limiting amplifier-   317 monitoring photo-diode-   318 trans-impedance amplifier bandwidth control-   319 feedback control line-   320 electrical signal output-   321 monitoring optical signal-   330 electrical signal input-   340 micro-controller user command input-   350 optical signal input-   360 optical signal output-   370 bandwidth controller user command input-   411 electrical to optical converter device-   412 driver circuits-   413 micro-controller/EEPOT-   414 optical-to-electrical converter-   415 trans-impedance amplifier-   416 limiting amplifier-   417 Monitoring photo-diode-   418 Trans-impedance amplifier bandwidth control-   419 Physical Media Attachment (PMA)-   420 Physical Coding Sublayer (PCS)-   430 Media Independent Interface (MII) electrical signal output-   440 Media Independent Interface (MII) electrical signal input-   450 Micro-controller user command input line-   460 Optical signal input-   470 optical signal output-   480 bandwidth controller user command input-   490 feedback control line-   511 electrical to optical converter device-   512 driver circuits-   513 micro-controller/EEPOT-   514 optical-to-electrical converter-   515 trans-impedance amplifier-   516 limiting amplifier-   517 monitoring photo-diode-   518 trans-impedance amplifier bandwidth control-   519 Physical Media Attachment (PMA)-   520 Physical Coding Sublayer (PCS)-   521RxTx data rate detector-   530 Media Dependent Interface electrical signal output-   540 Media Dependent Interface electrical signal input-   550 Micro-controller data rate set up input-   560 optical signal input-   570 optical signal output-   580TxRx data rate detector-   581 Bandwidth controller set up input-   590 fine tune control signal

What is claimed is:
 1. An optical transceiver that receives andtransmits signals of various data rates and power levels, comprising: anelectrical interface comprising an electrical input port that receivesan input electrical signal, a first user command input port thatreceives a first user command signal, an electrical output port thatoutputs an electrical output signal and a second user command input portthat receives a second user command signal; an optical interfacecomprising an optical input port that receives an input optical signalbased on which the electrical output signal is generated at theelectrical interface, and an optical output port that outputs an opticaloutput signal based on the electrical input signal received at theelectrical interface; a driver circuit coupled to the electrical inputport to receive the electrical input signal and responsive to a controlof the first user command signal in converting the electrical inputsignal into a driver signal at a data rate that is based on and varieswith the first user command signal, the driver circuit coupled toreceive a power feedback control signal and controlling a power level ofthe driver signal based on the received power feedback control signal;an electrical to optical converter coupled to the driver circuit toconvert the driver signal into the optical output signal carrying dataof the driver signal at the data rate; a monitoring photo diode thatdetects light of the optical output signal to generate the powerfeedback control signal to the driver circuit; an optical to electricalconverter coupled to the optical input port and converting the inputoptical signal into a first electrical signal; an amplifier coupled tothe optical to electrical converter to receive and amplify the firstelectrical signal to generate the output electrical signal, theamplifier receiving a bandwidth control signal and adjusting a bandwidthof the amplifier in generating the output electrical signal in responseto the bandwidth control signal; and a bandwidth controller coupled toreceive the second user command signal and producing the bandwidthcontrol signal based on the second user command signal.
 2. The opticaltransceiver as in claim 1, wherein the electrical interface comprises aPhysical Media Attachment block (PMA) coupled to the amplifier and thedriver circuit, configured to receive the output from the amplifier andto transmit the input electrical signal to the driver circuit.
 3. Theoptical transceiver as in claim 2, wherein the electrical interfacecomprises a Physical Coding Sublayer block (PCS) coupled to the PhysicalMedia Attachment block (PMA), configured to receive output from thePhysical Media Attachment block and transmits the input electricalsignal to the Physical Media Attachment block.
 4. An optical transceiverthat receives and transmits signals of various data rates and powerlevels, comprising: an electrical interface comprising an electricalinput port that receives an input electrical signal, and an electricaloutput port that outputs an electrical output signal; an opticalinterface comprising an optical input port that receives an inputoptical signal based on which the electrical output signal is generatedat the electrical interface, and an optical output port that outputs anoptical output signal based on the electrical input signal received atthe electrical interface; a driver circuit coupled to the electricalinput port to receive the electrical input signal and responsive to atransmitter data control signal in converting the electrical inputsignal into a driver signal at a data rate that is based on and varieswith the transmitter data control signal, the driver circuit coupled toreceive a power feedback control signal and controlling a power level ofthe driver signal based on the received power feedback control signal; atransmitter data rate detector coupled to detect a data rate of theinput electrical signal and producing the transmitter data controlsignal; an electrical to optical converter coupled to the driver circuitto convert the driver signal into the optical output signal carryingdata of the driver signal at the data rate; a monitoring photo diodethat detects light of the optical output signal to generate the powerfeedback control signal to the driver circuit; an optical to electricalconverter coupled to the optical input port and converting the inputoptical signal into a first electrical signal; an amplifier coupled tothe optical to electrical converter to receive and amplify the firstelectrical signal to generate the output electrical signal, theamplifier receiving a bandwidth control signal and adjusting a bandwidthof the amplifier in generating the output electrical signal in responseto the bandwidth control signal; a receiver data rate detector coupledto detect a data rate of the first electrical signal output by theoptical to electrical converter and producing the receiver data controlsignal based on the detected data rate; and a bandwidth controllercoupled to receive the receiver data control signal and producing thebandwidth control signal based on the receiver data control signal. 5.The optical transceiver as in claim 4, wherein the electrical interfacecomprises a Physical Media Attachment block (PMA) coupled to theamplifier and the driver circuit, configured to receive the output fromthe amplifier and to transmit the input electrical signal to the drivercircuit.
 6. The optical transceiver as in claim 5, wherein theelectrical interface comprises a Physical Coding Sublayer block (PCS)coupled to the Physical Media Attachment block (PMA), configured toreceive output from the Physical Media Attachment block and transmitsthe input electrical signal to the Physical Media Attachment block. 7.An optical transceiver, comprising: an electrical interface thatreceives an input electrical signal and that outputs an electricaloutput signal; an optical interface that receives an input opticalsignal on which the electrical output signal is based and that outputsan optical output signal based on the electrical input signal; a drivercircuit that converts the electrical input signal into a driver signal,the driver circuit generating the driver signal at a power that is basedon a feedback control signal; an electrical to optical converter coupledto the driver circuit to convert the driver signal into the opticaloutput signal, the optical output signal carrying data of the driversignal at a first data rate, the electrical to optical converteroutputting the optical output signal at a variable output powercontrolled by a receiver data control signal; a photo diode thatmonitors the optical output signal and generates the feedback controlsignal; an optical to electrical converter that converts the inputoptical signal into a first electrical signal; an amplifier coupled tothe optical to electrical converter to amplify the first electricalsignal and generate the output electrical signal, the amplifier having amodifiable bandwidth that is controlled by the receiver data controlsignal.
 8. The optical transceiver as in claim 7, further comprising areceiver data rate detector coupled to detect a data rate of the firstelectrical signal, the receiver data rate detector producing thereceiver data control signal based on the detected data rate of thefirst electrical signal.
 9. The optical transceiver as in claim 7,wherein the receiver data control signal is controlled by software. 10.The optical transceiver as in claim 7, wherein the optical interfacedetermines an operation mode for the optical transceiver throughhand-shaking.
 11. The optical transceiver as in claim 10, wherein theoperation mode sets the first data rate and a data rate of the inputoptical signal through remote provisioning by a link party.
 12. Theoptical transceiver as in claim 8, wherein the amplifier comprises (i) atransimpedance amplifier receiving the first electrical signal andproviding an amplified electrical signal, and (ii) a limiting amplifierreceiving the amplified electrical signal and providing the outputelectrical signal.
 13. The optical transceiver as in claim 12, whereinthe receiver data rate detector controls a bandwidth of thetransimpedance amplifier, a difference in the bandwidth of thetransimpedance amplifier results in a difference in sensitivity of theinput optical signal, and the sensitivity of the input optical signal ismodified to fit a data rate of the input optical signal.
 14. The opticaltransceiver as in claim 8, wherein the receiver data rate detector isconfigured to control frequency response characteristics of theamplifier.
 15. An optical transceiver, comprising: an electricalinterface that receives an input electrical signal and that outputs anelectrical output signal; an optical interface that receives an inputoptical signal on which the electrical output signal is based and thatoutputs an optical output signal based on the electrical input signal; adriver circuit receiving the electrical input signal or a variationthereof, and producing a driver signal at a data rate that is based onand that varies with a transmitter data control signal, the drivercircuit receiving a feedback control signal controlling a power of thedriver signal; an electrical to optical converter coupled to the drivercircuit to convert the driver signal into the optical output signal, theelectrical to optical converter outputting the optical output signal ata variable output power that is based on and that varies with thetransmitter data control signal; a photo diode that monitors the opticaloutput signal and generates the feedback control signal; an optical toelectrical converter that converts the input optical signal into a firstelectrical signal; an amplifier coupled to the optical to electricalconverter, to receive and amplify the first electrical signal andgenerate the output electrical signal, the amplifier having a modifiablebandwidth that is controlled by a bandwidth control signal; and abandwidth controller coupled to receive the transmitter data controlsignal, the bandwidth controller producing the bandwidth control signal.16. The optical transceiver as in claim 15, wherein the photo diode (i)monitors an intensity, power or strength of a monitoring optical signalfrom the electrical to optical converter and (ii) produces the feedbackcontrol signal in accordance with or based on the intensity or strengthof the monitoring optical signal.
 17. The optical transceiver as inclaim 15, wherein the driver circuit produces a bias voltage and adriving current for the electrical to optical converter, and thefeedback control signal is configured to modify or adjust the biasvoltage and/or the driving current of the driver circuit to control theoutput power of the optical output signal.
 18. The optical transceiveras in claim 17, wherein the output power of the optical output signal isregulated by an EEPROM having values set by the feedback control signal.19. The optical transceiver as in claim 17, further comprising amicro-controller that controls the bias voltage and the driver currentof the driver circuit.
 20. The optical transceiver as in claim 19,wherein the electrical interface further comprises a user command inputthat receives a user command signal, and the micro-controller receivesthe user command signal.
 21. The optical transceiver as in claim 19,wherein the micro-controller includes a memory to store softwareinstructions.
 22. The optical transceiver as in claim 19, furthercomprising a transmitter data rate detector coupled to detect a datarate of the electrical input signal and producing the transmitter datacontrol signal based on the detected data rate of the first electricalsignal.
 23. The optical transceiver as in claim 15, wherein thetransmitter data control signal is controlled by software.
 24. Anoptical transceiver, comprising: an electrical interface that receivesan input electrical signal and that outputs an electrical output signal;an optical interface that receives an input optical signal on which theelectrical output signal is based and that outputs an optical outputsignal based on the electrical input signal; a driver circuit receivingthe electrical input signal or a variation thereof, and producing adriver signal at a data rate that is based on and that varies with atransmitter data control signal, the driver circuit receiving a feedbackcontrol signal controlling a power of the driver signal; an electricalto optical converter coupled to the driver circuit to convert the driversignal into the optical output signal, the electrical to opticalconverter outputting the optical output signal at a variable outputpower that is based on and that varies with the transmitter data controlsignal; a photo diode that monitors the optical output signal and thatgenerates the feedback control signal; an optical to electricalconverter that converts the input optical signal into a first electricalsignal; an amplifier coupled to the optical to electrical converter toamplify the first electrical signal and generate the output electricalsignal, the amplifier having a modifiable bandwidth that is controlledby a bandwidth control signal; and a bandwidth controller coupled toreceive a receiver data control signal, the bandwidth controllerproducing the bandwidth control signal.
 25. The optical transceiver asin claim 24, wherein a change in data rate of the input optical signalchanges the bandwidth of the amplifier, and a change in the transmitterdata control signal changes a data rate and power of the optical outputsignal.
 26. The optical transceiver as in claim 24, wherein theelectrical interface further comprises a user command input thatreceives a user command signal.
 27. The optical transceiver as in claim26, wherein the user command signal consists of a single control signalthat sets data transmission and data reception at a same rate.
 28. Theoptical transceiver as in claim 26, wherein the user command signalcomprises first and second control lines that allow different data ratesfor data transmission and data reception.
 29. The optical transceiver asin claim 28, further comprising a micro-controller that receives thetransmitter data control signal on the first control line, wherein thebandwidth controller receives a second user command signal on the secondcontrol line, the bandwidth controller producing the bandwidth controlsignal based on the second user command signal.
 30. The opticaltransceiver as in claim 24, further comprising: a) a receiver data ratedetector coupled to detect a data rate of the first electrical signal,the receiver data rate detector producing a receiver data control signalbased on the detected data rate of the first electrical signal, and thebandwidth controller producing the bandwidth control signal based on thereceiver data control signal; b) a transmitter data rate detectorcoupled to detect a data rate of the electrical input signal andproducing a data rate set up signal; and c) a micro-controller thatreceives the data rate set up signal and controls a bias voltage and adriving current of the driver circuit.
 31. The optical transceiver as inclaim 24, wherein the bandwidth control signal is controlled bysoftware.
 32. The optical transceiver as in claim 24, wherein theoptical interface determines an operation mode for the opticaltransceiver through hand-shaking, and the operation mode sets the firstdata rate and a data rate of the input optical signal through remoteprovisioning by a link party.
 33. The optical transceiver as in claim24, wherein the amplifier comprises: a) a transimpedance amplifierreceiving the first electrical signal and providing an amplifiedelectrical signal, wherein the bandwidth controller controls a bandwidthof the transimpedance amplifier, and b) a limiting amplifier receivingthe amplified electrical signal and providing the output electricalsignal.
 34. The optical transceiver as in claim 24, wherein thebandwidth controller is configured to control frequency responsecharacteristics of the amplifier.
 35. A method of receiving andtransmitting optical signals, comprising: converting an electrical inputsignal into a driver signal at a data rate that is based on and thatvaries with a first command signal; converting the driver signal into anoptical output signal and at a variable output power that is based onand that varies with the first command signal, the optical output signalcarrying data of the driver signal; converting an input optical signalinto a first electrical signal; and amplifying the first electricalsignal to generate an output electrical signal, the first electricalsignal having a modifiable bandwidth that is controlled by a secondcommand signal.
 36. The method as in claim 35, wherein a difference inthe modifiable bandwidth of the first electrical signal results in adifference in sensitivity of the input optical signal, and thesensitivity of the input optical signal is modified to fit a data rateof the input optical signal.
 37. The method as in claim 35, wherein thefirst command signal and the second command signal are represented byone or more mode signals that set desired data rates for datatransmission and data reception.
 38. The method as in claim 35, whereina change in the first command signal changes a data rate of the opticaloutput signal, and a change in the second command signal changes a datarate of the optical input signal.
 39. The method as in claim 35, whereinthe power of the driver signal corresponds to a bias voltage and adriving current, and the method further comprises controlling a power ofthe driver signal based on a feedback control signal, the feedbackcontrol signal adjusting the bias voltage and/or the driving current tocontrol an output power of the optical output signal.
 40. The method asin claim 35, further comprising determining an operation mode for theoptical transceiver through hand-shaking.
 41. The method as in claim 40,wherein the operation mode sets the data rates of the driver signal andthe input optical signal through remote provisioning by a link party.